1. Peel your sweet potato and cut into chunks and boil until soft. Then mash and cover with foil to keep warm.
2. Now you can make your pie filling. Heat your extra virgin olive oil on a medium heat in your non-stick pan. Add garlic, pepper and onion and fry until softened.
Add your seitan, cumin, paprika, and mixed herbs and cook evenly, stirring regularly until your Seitan has browned.
Add your diced tomatoes and stir thoroughly, put the lid on and leave to simmer for around 20 minutes.
Place your filling into a small oven proof dish and top with your mashed sweet potato and grill on a medium heat until your potato has browned to your liking.